What's wrong seems to be that you made the mistake of accepting Microsoft's relentless nagging to convert your OS from Windows 10 to Windows 11, which is obviously not designed to work with older hardware with older audio parameters. MS is telling people to go buy a new computer with an upgraded intel chip that Win 11 was written to work with. Aint that nice.
I have a new (12/2023) Dell XPSi7 with Win 11 pre-installed and the latest RealTek and NVidia cards and drivers. And I'm suddenly getting the same message: "No audio device is installed." So the problem lies elsewhere....but where?